Early in the debate the Fox News moderator brought up the 'Minnesota Nice" cliché, asking Pawlenty whether Bachmann is unqualified to be president.

And unlike the last debate when Pawlenty backed away from directly criticizing Mitt Romney, Pawlenty didn't miss a beat going after Bachmann.

"It's an undisputable [sic] fact that in Congress her record of accomplishment and results is nonexistence," Pawlenty said. "That's not going to be good enough for our candidate for President of the United States."

Bachmann looked unfazed by the criticism and took it up a notch, saying Pawlenty's record is not conservative enough.

"Governor, when you were governor in Minnesota you implemented 'cap and trade' in our state and you praised the unconstitutional individual mandate and you called for requiring all people in our state to purchase health insurance the government would mandate," she said. "Third, you said the era of small government was over. That sounds more like Barack Obama to me."

GOP candidates debateCharlie Neibergall/ASSOCIATED PRESS

And the battle raged on, getting more personal as Pawlenty bluntly tried to make the case that Bachmann plays fast and loose with the truth.

"She's got a record of misstating and making false statements," he said.

Then Pawlenty accused Bachmann of being ineffectual.

"She fought for less government spending, we got a lot more. She led the effort against ObamaCare, we got ObamaCare. She led the effort against TARP, we got TARP," he said. "She says she's got a titanium spine; it's not her spine we're worried about, it's your record of results. If that's your view of effective leadership, of results, please stop because you're killing us."

Bachmann defended her history of battling Democrats right up to the latest fight over the debt ceiling.

"I was effectively taking them on nearly every argument they put forward," she said. "I fought, when others ran, I fought and I led against increasing the debt ceiling."

Peace — or at least silence — then reigned between Bachmann and Pawlenty, but only for about 20 minutes. Then they were at it again.

The issue was Pawlenty's support for a 75-cent per-pack fee on cigarettes in Minnesota. Bachmann voted for the so-called "health impact fee," but said that had she not, she would've undercut protections against legalized abortion.

Pawlenty said the abortion issue had nothing to do with Bachmann's yes vote.

"Congresswoman Bachmann didn't vote for that bill because of stripping away of pro-life protection. She voted for it and is now creating that as an excuse," he said. "But nonetheless she speaks of leading these effort in Washington and Minnesota. Leading and failing is not the objective. Leading and getting results is the objective. I've got the best record of results of any candidate in this race."

Bachmann accused Pawlenty of cutting a bad deal.

"We need to have a president of the United States who stands firm on their convictions," she said. "This is what I have demonstrated every day that I've been in Congress."

Both the Bachmann and Pawlenty campaigns claimed victory following the debate. One political observer said the spirited exchanges between Bachmann and Palwenty probably had a lot to do with their fierce competition in this weekend's Ames Straw Poll.

But their arguments and those between some of the other candidates probably made presumed GOP frontrunner Mitt Romney look more presidential. And looming above the entire debate is the expected entrance of Texas Gov. Rick Perry into the race this weekend. Polls show he already has more support among Republicans than both Bachmann and Pawlenty combined.